Pressure system charging tool and method



Jan. 24, 1967 R. B. WHITE ETAL 3,299,648

PRESSURE SYSTEM CHARGING TOOL AND METHOD Filed May 20, 1965 5 Shee sheet l CONDENSOR COMPRESSOR EVAPORATOR -L 1 1 2 Av 'l MA 4o 76 36 so 68 96 6O '70 56 /72 82 [0Q 32\ 78 I02 94 l 66 98 62 58 so 54 a4 86 as 90 INVENTORS RICHARD B. WHITE JUNIOR L.FR|TCH ATTORNEYS Jan. 24, 1967 R. B. WHITE ETAL PRESSURE SYSTEM CHARGING TOOL AND METHOD 3 Sheets-Sheet 2 Filed May 20, 1965 lNl/ENTORS RICHARD 8. WHITE 'JUNIOR L. FRITCH @Mz 6 Paw/41M ATTORNEYS Jan. 24, 1967 R. B. WHITE ETAL PRESSURE SYSTEM CHARGING TOOL AND METHOD 5 Sheets-$heet '5 Filed May 20, 1965 QNN INVENTORS RICHARD 8. WHITE JUNIOR L FRITCH QWN @MN @wzma wuw,

ATTORNEYS United States Patent 3,299,648 PRESSURE SYSTEM CHARGING TOOL AND METHOD Richard B. White, Royal Oak, Mich., and Junior L.

Fritch, Edgerton, Ohio, assignors to Kent-Moore Organization, Inc., Warren, Mich, a corporation of Michigan Filed May 20, 1965, Ser. No. 457,443 6 Claims. (CI. 62-77) This invention relates to a method and tool particularly, though not exclusively, well adapted for use in the evacuation and charging of refrigeration systems.

Many refrigeration systems, such as an automotive airconditioning system, are presently provided with a Schrader or tire valve at the refrigerant charge and discharge ports, rather than a manual shutofl? valve, because of the cost saving in using a Schrader valve. As a consequence of this saving, the automotive refrigeration systems are now almost universally supplied with a Schrader valve at the high and low pressure side of the compressor.

The method heretofore employed in evacuating and charging the refrigeration systems is to depress the Schrader valve core with a special adapter fitting. This method creates several problems because the valve core remains in the valve and greatly restricts the flow path. This restriction greatly increases the time required for recharging. Further, the adapter fitting may damage or jam the valve core, causing the loss of refrigerant and possible injury to the operator.

In evacuating and charging a refrigerator system, the first step in the operation is to bleed the compressor of refrigerant, usually Freon, which is allowed to escape to the atmosphere. The rate of discharge of refrigerant must be controlled to prevent the loss of oil contained in the compressor. According to the prior art practice, the

only control of discharge is a manual shutoff valve on the discharge line. Should a leak or break occur in this line the refrigerant flow cannot be controlled in time to prevent loss of the compressor oil. The sudden escape of refrigerant may also injure the operator.

The system is then evacuated of air by a vacuum pump, which requires approximately twenty minutes due to the restricted fiow through the Schrader valve.

Finally the system is recharged with refrigerant. This operation requires the refrigerant to be forced through the small orifice in the Schrader valve which has the effect of vaporizing the liquid refrigerant and filling the system with gas before all the liquid refrigerant has entered the system. As a consequence it is necessary to operate the compressor to literally pump the refrigerant into the system which may be harmful to the expansion valve. Further, should the stem become jammed in the valve the entire refrigerant charge may be lost when the lines are removed. This charging operation takes from ten to fifteen minutes because of the restricted valve flow and the requirement of operating the compressor.

This invention removes the Schrader valve core while maintaining the pressure in the compressor, thereby allowing unrestricted fiow through the Schrader valve body. The tool which performs this operation comprises a body having a female threaded coupling adapted to be connected to the exterior of the Schrader valve nipple. The

Patented Jan. 24, 1967 tool body is provided with a lateral port which communicates with the evacuating and charging lines. Extending axially through the body is a stem provided with jaw means at its inner end which may be pressed over the Schrader valve core to grip it. The stem is reciprocable and rotatable, and its outer end is provided with a handle.

The tool is then coupled to the Schrader valve nipple and the stem is depressed to engage the valve core. The stem is rotated to unthread the core, and then withdrawn to withraw the core out of the nipple beyond the lateral port in the tool body. The tool now has an unrestricted flow path for refrigerant between the valve and the lateral port. When evacuation and charging has been completed,

the stem is depressed and rotated to threadedly reset the Schrader valve core in the valve body.

This invention eliminates the possibility of damaging or jamming the valve core as it is removed during evacuation and charging. The evacuation time is reduced by over 60% and the charging time is reduced by over Further, the valve stem may be forced into the valve during discharge of the expired refrigerant to control or stop the discharge of refrigerant to prevent the loss of oil in the compressor, or injury to the operator, in case of a leak or break in the discharge line.

The principal object of this invention is therefore to provide a method and tool used in the evacuation and charging of refrigeration systems which:

Reduces the evacuation time by over 60%;

Reduces the charging time by over 90%;

Provides better control over the discharge of expired refrigerant to prevent the loss of oil in the compressor;

Provides a safer method of evacuating and charging the refrigeration system;

Prevents the damage or jamming of the valve core.

Other objects, advantages, and meritorious features of this invention will more fully appear from the following specification, claims, and accompanying drawings, wherein: Y

FIG. 1 is a schematic illustration of a refrigeration system, such as an automotive air-conditioning system, with the tool of this invention attached to the high pressure side of the compressor;

FIG. 2 is a cross-sectional view of one embodiment of the tool of our invention showing the grappling means extended to contact the Schrader valve;

FIG. 3 is the embodiment shown in FIG. 2 with the grappling means and the Schrader valve core fully withdrawn from the valve port;

FIG. 4 is a partial sectional view of the grappling head of FIG. 2, showing details of construction;

FIG. 5 is a sectional end view of FIG. 4 along viewlines 5-5;

FIG. 6 is a cross-sectional view of another embodiment of our invention with the grappling means and Schrader valve core retracted beyond the lateral port;

FIG. 7 is the embodiment shown in FIG. 6 with the grappling means extended to contact the Schrader valve;

FIG. 8 is a partial cross-sectional view of the grappling head shown in FIG. 6;

FIG. 9 is a partial sectional view of another embodiment of our invention similar to FIG. 6; and

FIG. 10 is a cross-sectional view of a simplified embodiment of our invention.

Referring now to FIG. 1 in which we schematically show a refrigeration system connected for evacuating and charging. The refrigeration system we have illustrated is conventional in automotive air-conditioning systems. Low pressure refrigerant vapor is drawn into the compressor 20 at its low pressure side 30, where it is compressed to a high pressure, high temperature vapor, and forced into the condenser 24, located in front of the automobile radiator, not shown. In the condenser 24, the vaporized refrigerant is changed to a high pressure, high temperature liquid as its latent heat escapes to the lower temperature air drawn through the condenser by the engine fan. The high pressure high temperature liquid from the condenser 24 is then forced into the expansion valve 26 on the evaporator assembly. The high pressure liquid then changes to a low pressure liquid and vapor, as it forces its way through the valve into the inlet pipe of the evaporator 28. In the evaporator 28 some of the heat from the air circulating in the air-conditioning system is given up to the cold evaporator tubes, causing the liquid refrigerant to vaporize. The refrigerant vapor is then drawn into the low pressure inlet 30, of the compressor 20, where the cycle is repeated.

A conventional automotive air conditioner is provided with two Schrader valves, one on the high pressure side as shown at 32, and one on the low pressure side, as shown at 34. The tool of our invention, generally indicated at 36, is connected to the Schrader valve 32, at the high pressure side of the compressor 20. The evacuating and charging line 38 is connected to the lateral port of the tool 40. The system is now ready for the evacuating and charging operations.

Referring now to FIGS. 2 through 5, wherein we show the structure of one embodiment of the tool. The tool body 50 has a cylindrical bore 52 throughout its length, forming a chamber 54 of a diameter slightly larger than the core of a Schrader valve. The forward end of the chamber communicates wtih the nipple of a Schrader valve, indicated generally at 32. The forward end 56, of the body member 50, has a 45-degree counterbore 58, which mates with the corresponding projecting end 60 of the Schrader valve. A soft copper washer 62 is provided between the mating surfaces, to seal the interior of the Schrader valve 64 for communication with the tool body chamber 54. A turnbuckle nut 66 is threaded to the exterior of the valve 68 at one end, and to the threaded portion of the body 70, at its opposite end. The threads 70, on the forward end of the body member 50, are left-handed, and the threads 68, which attach to the Schrader nipple, are right-handed. This provides a turnbuckle arrangement, which allows the lateral port, generally indicated at 40, to be positioned as required before tightening of the nut 66.

The lateral port is threaded at 72 to receive a short threaded nipple, to provide communication between the tool chamber 54 and the charging and evacuating line, generally indicated at 38. The threaded nipple 74 is permanently threaded into the tool body member 50, and a Weatherproofing may be provided on the mating threads, such as Teflon tape.

The aft end of the tool, generally indicated at 76, is threaded at 78 to receive a seal-retaining nut 80, and the chamber 54 has a counterbore 82, which receives the sealing means. The sealing means includes a metal washer 84, an asbestos-filled Teflon insert 86, and a brassretaining insert 88. The seal-retaining nut 80 has a flange 90 to engage the end of the brass insert 88, on tightening of the nut 80, providing an adjustable pressure packing gland for the grappling stem 92. It can be seen that by tightening the nut 80, the Teflon insert 86 is sealingly compressed against the grappling stem 92. A proper seal has been attained by tightening the nut 80, until one and one-half to two pounds force is required to laterally move the stem 92.

The grappling means of FIG. 2 is shown extended to engage the Schrader core valve 94. The grappling means of this embodiment includes a head 96 integral with the stem 92, a retaining or stop ring 98, copper brazed to the stern, and a handle 100, retained on the aft end of the stem 92 by a .setscrew 102. The construction of the grappling head 96 is best shown in FIGS. 4 and 5. The core engaging end of the head 96 is bifurcated to present two tongs 104. The tongs 104 firmly grip the rectangular portion 106 of the Schrader valve core 94.

The Schrader valve shown is conventional. The valve core 94 is externally threaded at 108 to be threadedly received within the valve body chamber 64, at 110. The grappling means is rotatably and axially shiftable within the chamber 54 in response to manual manipulation of the handle 100. During the evacuation and charging operation the valve core 94 is removed from the valve chamber 64, to allow unrestricted communication between the valve chamber 64, communicating with the high pressure side of the compressor as shown in FIG. 1, and the evacuation and charging lines 38, shown in FIGS. 1 and 2.

To install and operate the tool, the nut 66 is first loosened to within a few turns of the threads 70, the grappling means is fully withdrawn, to the position shown in FIG. 3. The nut 66 is then threaded on the threaded portion 68 of the Schrader core nipple 32, and the body member threads 70, by clockwise rotation, with the threaded nipple 74 aligned for communication with the evacuation and charging lines 38. The turnbuckle effect of the nut 66, provided by its right and left-handed threads, allows the nipple 74 to be positioned before the tool is attached. It is also noted that the lines may be connected to the tool 36 before attachment to the Schrader nipple 32;

After the tool is attached to the valve, the grappling means is extended, by manual operation of the handle 100, to engage and grip the Schrader core 94. This is accomplished by slowly rotating the handle 100, until the tongs 104 seat on the rectangular extending portion 106, of the core 94. The core of the Schrader valve may now be unthreaded from the valve chamber 64, by rotating the handle of the grappling means counterclockwise. Rotation is continued until further rotation no longer results in a further extending of the handle away from the body 50, indicating that the valve core 94, is free within the tool chamber 54. The grappling means may now be fully retracted, to the position shown in FIG. 3, where the body of the Schrader core valve stem 94 no longer interferes with the communication between the compressor and the evacuating and charging lines 38. The stop 98 will engage the washer 84 to indicate the full extent of travel. The system is now ready for evacuating and changing.

After the charging operation the Schrader core 94 is rethreaded into the valve chamber 64 by reversing the steps described above. The grappling means is extended until the threads of the core 108 engage the threads 110 in the valve body chamber 64. The core then may be rethreaded into the chamber, by clockwise rotation of the handle 100, until a firm engagement is made. After repeated operations the grappling tongs 104 may require tightening, which is accomplished by applying a slight pressure with the fingers to force the tongs to gether.

FIGS. 6, 7 and 8 illustrate another embodiment of the tool of our invention. This embodiment facilitates connection of the tool to the Schrader nipple in restricted areas. The Schrader valve illustrated is conventional, and is numbered the same as in FIGS. 2 through 5.

The tool body has a cylindrical sealed chamber 154, of a diameter slightly larger than the diameter of the Schrader valve core 94. The forward end of the tool body 150, is provided with a counterbore 156, to receive a soft copper extension tube 158, having a 45- degree flared end 160. The copper tube 158 is detachably held in sealed communication with the body chamber 154, by a metal ferrule 162, and an O-ring 164, received within a counterbore 166. A nut 168 threadably locks the assembly within the body member 150. A 45-degree flare nut, 170, detachably and sealingly secures the flared tube 158 to the forward end of the valve nipple 32. The flare nut 170 has an internal surface 250 at a 45-degree angle, relative to its axis, which mates with flared end of the tube 160. An O-ring 252 abuts the end of the flared tube, and is retained within the nut by an internal flange 254. A satisfactory 'seal is obtained by hand-tightening the nut 170, which eliminates overtightening, and the exterior surface of the nut is knurled at 256 to provide a gripping surface. The tool is provided with a threaded lateral port 172 and a short nipple 174 similar to FIGS. 2 through 5.

The grappling means of this embodiment includes a stem 202, a handle 200 secured by a setscrew 201, and a head, generally indicated at 204, and best shown in FIGS. 6 to 8. A grappling head element 206 is secured to a reduced portion of the grappling stem 207 by a roll pin 208. An O-ring 210 is secured within the bifurcated end of the grappling head 206, by a groove 212 within the grappling head 206, and the end of the grap pling stem 202. An axial bore 214 in the end of the grappling stem 202 receives the extending head 220 of the Schrader valve core. The grappling tongs 216 receive the Schrader core rectangular portion 106, similar to FIG. 4, but do not retain the Schrader core, as in FIG. 4. The Schrader valve core 94 is retained by the O-ring 210. When the grappling head 206 is seated on the Schrader valve core 94, the projecting head 220 of the core is forced past the O-ring 210 into the stem bore 214 where it is restrained for manipulation within the tool chamber 154. The restraining action of the O-ring 210 is sufficient to prevent separation of the core from the grappling means during normal operation. However, if the valve core does separate from the grappling means within the chamber, the grappling means is extended toward the core to reseat the core. The cylindrical tool chamber 154 will maintain the core in alignment for reengagement.

The aft end of the chamber 154 is sealed against the grappling stem 202 by an O-ring 222, received within a groove 224 in the body 150.

The operation of the tool of this embodiment, after installation on the Schrader valve nipple 32, is the same as that described in reference to FIGS. 2 through 5. To install the tool on the Schrader valve nipple 32, the nut 168 is loosened sufficiently to remove the flared tube 158. The flared tube 158 is then separately secured to the projecting end of the Schrader valve 32 by the nut 170. With the grappling means fully retracted, as shown in FIG. 6, and the lateral port 172 positioned for connection to the evacuating and charging lines, the tool body 150 is slid over the exposed end of the flared tube 158, until it seats in the counterbore 156. The nut 168 is then securely tightened, to provide a sealed communication between the Schrader valve chamber 64 and the tool body chamber 154.

This embodiment allows the operator to attach the flared extension tube 158 in a restricted area. The length of the flared tube 158 may be varied, as required by the access available to the Schrader valve 32.

FIG. 9 illustrates a modification of the embodiment of FIGS. 6 and 7, wherein the flared end tube 158 is permanently retained in the tool body counterbore 156, to prevent the tube from being blown out of body 150 in extremely high pressure applications. In this embodiment the aft end of the tube 300 is slightly flared, after it is seated in the counterbore 156, and two O-rings, 302 and 304, are provided in the second counterbore 166. This permanently retains the tube against blow-out. The other elements are the same as in FIGS. 6 to 8.

The method of installing the embodiment of FIG. 9

is similar to the method described in reference to FIGS. 2 to 5, except the flare nut 170 swivels on the flared end of the tube when it is attached to the valve nipple 32.

FIG. 10 illustrates a simplified modification of the tool shown in FIGS. 6 and 7. In this modification the flared tube 350 is an integral extension of the tool body 150, and the threaded nipple 374 is seated in a counter bore 375 in the body 150, and secured as by brazing or other means. Other elements of this embodiment are the same as shown in FIGS. 6 and 7.

It is understood that both of the embodiments we have disclosed have their respective advantages, and the advantageous features of these embodiments are interchangeable. For example, the grappling means of FIGS. 6 to 8 may be combined with the turnbuckle attachment of FIGS. 2 through 5, or the flared extension tube 158, of FIGS. 6 through 8, may be used in the embodiment of of FIGS. 2 to 5.

What is claimed is:

1. An evacuating and charging tool for use with a refrigeration system having a threaded port provided with a removable threaded Schrader valve core comprising; a body member having a sealed elongated chamber opening at one end for sealed communication with said threaded port, said body member having a laterally extending port for communication with evacuating and charging lines, and an operating shaft extending through and supported by the chamber wall opposite said opening, said operating shaft having a Schrader valve core grappling means located within said chamber at its inner end, a control means located outside of said chamber, said grappling-means rotatably and axially shiftable within said chamber in response to said control means and having a bifurcated end received over said Schrader valve core to frictionally retain said core to effect unthreading of said valve core on rotation, and withdrawal of said valve core in response to axial motion of said control means to a'position within said sealed chamber between said laterally extending port and said chamber wall opposite said opening where it does not restrict the flow passage between said ports during evacuating and charging of said compressor, said grappling means also shiftable within said chamber in response to said operating means to rethread and tighten said valve core within said threaded port after the evacuating and charging operations.

2. The invention of claim 1 in which said elongated chamber is cylindrical throughout its length and has a diameter slightly larger than said Schrader valve core so that said grappling means can be operated to re-engage said core should s-aid closure and said grappling means become separated within said chamber.

3. The invention of claim 1, in which an O-ring is provided within said bifurcated end of said grappling means which frictionally engages and retains the stem portion of said Schrader valve core which prevents separation between said grappling means and said core within said chamber.

4. The invention of claim 1, wherein the sealed communication between said threaded port and said body member is effected by a flared end tube detachably secured and communicating with said chamber at the unfiared end of said tube, and a screw thimble nut threadably engaged within said chamber sealably holding said flared end of said tube in communication with sai threaded port.

5. A method of evacuating and charging the compressor of a refrigeration system through a Schrader valve type access fitting, including the steps of; (a) attaching a tool having a sealed chamber communicating with evacuating and charging lines to the projecting portion of the Schrader valve, (b) unthreading the core of said Schrader valve from the valve body and withdrawing it to a position within said sealed chamber where it does not restrict the flow path between the vessel and said evacuating and charging lines, (0) opening of said evacuating line to allow discharge of refrigerant from said compressor, and controlling the discharge of said refrigerant when neces- 'sary by forcing the valve oore toward the valve body to restrict the flow path through said valve body, (d) charging the compressor with refrigerant through said charging line into the high pressure side of said compressor only, (e) rethreading the core of said valve within said valve body with the compressor under pressure while said evacuating and charging lines are connected.

6. The method of claim 5 in which :said-Schrader valve I core is forced back toward the threaded port during evacuating and charging to control the rate of flow into or out of said vessel.

References Cited by the Examiner UNITED STATES PATENTS 1,830,894 11/1931 Ullstrand et a1. 6277 Althouse and Turnginst, Modern Refrigeration, Goodheart-Willcox, Chicago, 1956 (page 387 relied on).

LLOYD L. KING, Primary Examiner. 

1. AN EVACUATING AND CHARGING TOOL FOR USE WITH A REFRIGERATION SYSTEM HAVING A THREADED PORT PROVIDED WITH A REMOVABLE THREADED SCHRADER VALVE CORE COMPRISING; A BODY MEMBER HAVING A SEALED ELONGATED CHAMBER OPENING AT ONE END FOR SEALED COMMUNICATION WITH SAID THREADED PORT, SAID BODY MEMBER HAVING A LATERALLY EXTENDING PORT FOR COMMUNICATION WITH EVACUATING AND CHARGING LINES, AND AN OPERATING SHAFT EXTENDING THROUGH AND SUPPORTED BY THE CHAMBER WALL OPPOSITE SAID OPENING, SAID OPERATING SHAFT HAVING A SCHRADER VALVE CORE GRAPPLING MEANS LOCATED WITHIN SAID CHAMBER AT ITS INNER END, A CONTROL MEANS LOCATED OUTSIDE OF SAID CHAMBER, SAID GRAPPLING MEANS ROTATABLY AND AXIALLY SHIFTABLE WITHIN SAID CHAMBER IN RESPONSE TO SAID CONTROL MEANS AND HAVING A BIFURCATED END RECEIVED OVER SAID SCHRADER VALVE CORE TO FRICTIONALLY RETAIN SAID CORE TO EFFECT UNTHREADING OF SAID VALVE CORE ON ROTATION, AND WITHDRAWAL OF SAID VALVE CORE IN RESPONSE TO AXIAL MOTION OF SAID CONTROL MEANS TO A POSITION WITHIN SAID SEALED CHAMBER BETWEEN SAID LATERALLY EXTENDING PORT AND SAID CHAMBER WALL OPPOSITE SAID OPENING WHERE IT DOES NOT RESTRICT THE FLOW PASSAGE BETWEEN SAID PORTS DURING EVACUATING AND CHARGING OF SAID COMPRESSOR, SAID GRAPPLING MEANS ALSO SHIFTABLE WITHIN SAID CHAMBER IN RESPONSE TO SAID OPERATING MEANS TO RETHREAD AND TIGHTEN SAID VALVE CORE WITHIN SAID THREADED PORT AFTER THE EVACUATING AND CHARGING OPERATIONS. 